The paper presents explicit numerically implementable formulas for the Poincaré–Steklovoperators, such as the Dirichlet–Neumann, Dirichlet–Robin, Robin1–Robin2, and Grinberg–Mayergoizoperators, related to the two-dimensional Laplace equation. These formulas are based on thelemma about a univalent isometric mapping of a closed analytic curve onto a circle. Numerical resultsfor domains with very complex geometries were obtained for several test harmonic functions for theDirichlet–Neumann and Dirichlet–Robin operators